As promised here is the walk through with pictures on talking apart the Volvo M66 (C close ratio) manual trans.
Keep in mind that I'm have no plans on putting this one back together so it's extra dirty while I'm working on it in the shop. If were really going to build a trans you can bet I would keep all the parts sparkling clean and in a nice clean environment. Spend some time pressure washing the case of the trans ect. If you are doing this in your shop, have 3-4 large clean clear plastic containers with snap on lids, and several smaller tupperware or rubber maid containers so you can sort all of the parts in the trans into the different bins and not hurt anything. BE VERY GENTLE when pulling the case apart, and pulling the gear stacks and shift forks from the trans case.
If any of you are pulling out hair wondering why I took apart a perfect looking trans, this is from my parts car that was hit in the front. It broke the case in 4-5 spots, and also seems to have bent the surface where the trans mounts to the motor.
There are NO Special Volvo tools required. The most advanced tool you will need is a simple 2 jaw puller for pulling the clutch slave cylinder off of the input shaft of the trans.
Here's a pic of the tag on the trans telling you what it is in Volvospeak. You can see it say M66C and in the other spot says 3.7 which is the final drive ratio.
Before you start, make sure you pull the drain plug and fill plug to get all of the old gear oil out of the trans. It smells awful if you spill it all over the shop. This is what the drain and fill plugs look like. You will need 2 new copper crush washers if you're putting the trans back in for these plugs.
Here is my favorite tool for sucking out gear oil. Harbor Freight vac oil changer designed for boats. It has a venturi on it that you hook up to the shop's air supply, then you can roll it around and suck up gear oil out of different sumps ect.
Here is the trans up on my work bench ready to be pulled apart.
Here is a shot of the bolts that run all round the case of the trans. Typical Volvo tools, 12mm bolts around the exterior of the trans joining the 2 halves of the trans, and 1 12 mm hiding that you have to take out from inside the bell housing area where the clutch goes.
The the shift mechanism has to come out so the internals of the trans can come out. There are 4 bolts on top that come out, then some sort of shift detent that unscrews from the trans case below it. It looks like this:
Next step is to remove the Clutch slave cylinder. This is the infamous one that leaks that everyone hates, this is just a terrible design by Volvo having the slave internal to the trans so that when it leaks it costs thousands of dollars in labor to replace, and ruins a clutch. There is a 10 mill bolt holding it in, plus you have to unclip the supply line that brings in the brake fluid. Once those are off, bust out the 2 jaw puller and PB blaster and pull the slave off of the input shaft. Here is what the slave looks like after removal:
Now your are in the home stretch. You want to very genlty pry the 2 halves of the trans apart at the seam with a flat head screw driver, but DO NOT scrape up the flat mating surfaces with the screw driver as it could lead to a leak on reassembly. Here are some pics of the trans apart.
Here is what the other half of the trans case looks like inside.
Now very gently lift out the gear stacks and shift forks. If you have to turn the trans over for something, be very cautious not drop the differential which is the much larger gear you can see in the picture with all the bolts in it. Once the gear stacks and shift forks are all free the diff will come out with out any other work.
Here is a shot of the trash magnet that sits at the very bottom of the transmission and collects garbage. If I were building this tans, I would spend the $10 and buy a neodymium rare earth magnet that has a much stronger pulling force. Make sure it is grade N38 SH or above to insure that the magnetic force is not lost when the magnet heats up. I will update this thread with the exact dimensions of the magnet.
Shot of the diff out side the trans, this would be a good time to install a Qualife.
The shift forks out of the trans. One is missing from this photo.
This is what I've been running inside this trans for the last 5,000 mi or so. AMSoil GL4 75w90 Trans lube synthetic. No trans problems, with upgraded power and some aggressive driving. The shift quality also improved with this fluid.
I'm going to try to put together a web site with more Volvo FAQ's so that things don't just get lost forever in the depths of the forum.